Do you think my meter is broken or is it just having an "off" moment? I know meters can have a range, but I've never had this happen...
I changed my dexcom sensor tonight, and after 2 hours, it makes you calibrate with 2 separate BG's from the same meter. I actually felt low -- shows what I know! -- tested, and my meter said 302. I freaked out how I could be so high. Then, tested a 2nd time for the 2nd calibration, and it was 224. So, out of curiosity, tested a 3rd time and it was 242. Hmmm???
have you changed the batteries recently?
One of my cheap testing kits has done this before. If i have dropped it recently, gotten it wet, or the batteries are almost dead, it'll do that to me. Try changing the batteries
as far as your meter is concerned, 302, 242, and 224 are the same number. our meters are +/- 20% accurate if your reading is above 75 mg/dl. This is exactly why our (explicative deleted) meters are so bad. IMO I woudn't calibrate a cgm sensor above 120 for this reason. I would lie to the cgm or wait until I had a flat 45 minutes before entering a calibration.
good luck Sarah
Thanks for your replies guys. I just called One Touch, and they were great -- they're rushing me another meter b/c they said my current one sounds too erratic. (Um, yes!). In the future, I should try changing batteries too I think, but this time, it's all worked out.
[quote user="Joe"]
IMO I woudn't calibrate a cgm sensor above 120 for this reason. I would lie to the cgm or wait until I had a flat 45 minutes before entering a calibration.
[/quote]
Joe, unlike the medtronic CGM, you can calibrate the dexcom anywhere between 40 and 400, and your BG doesn't have to be flat when you do it. I've calibrated going up or down with no problem. But, the one thing you definitely don't want to do is lie or make up a number b/c then it would miscalibrate and misread all your future readings.
I have noticed that when I get too high, if I redo my blood test, the reading can vary quite a bit, but they are still high, so I treat accordingly. Once I get back to a "good" reading, they are more consistent. Also, every once in a while, I will feel like I am low, when I am actually high! I haven't been able to correlate this to anything, and since it rarely happens, maybe twice a year, I figure it's just a weird day.
[quote user="Sarah"]
Joe, unlike the medtronic CGM, you can calibrate the dexcom anywhere between 40 and 400, and your BG doesn't have to be flat when you do it. I've calibrated going up or down with no problem. But, the one thing you definitely don't want to do is lie or make up a number b/c then it would miscalibrate and misread all your future readings.
[/quote]but, if your meter is +/- 20% (TWENTY PERCENT ) wouldn't you calibrate under 100, simply because of your meter accuracy???
example: meter reading of 400, actual blood sugar 480 to 320... what exactly would you calibrate your cgm to? 400? 375? is it even close? under 100 your dealing with +/- 20 points... maybe I am too picky, but when I wear the cgm I expect a "lil bit" of trust and accuracy.
[quote user="Joe"]
[quote user="Sarah"]
Joe, unlike the medtronic CGM, you can calibrate the dexcom anywhere between 40 and 400, and your BG doesn't have to be flat when you do it. I've calibrated going up or down with no problem. But, the one thing you definitely don't want to do is lie or make up a number b/c then it would miscalibrate and misread all your future readings.
[/quote]
but, if your meter is +/- 20% (TWENTY PERCENT ) wouldn't you calibrate under 100, simply because of your meter accuracy???
example: meter reading of 400, actual blood sugar 480 to 320... what exactly would you calibrate your cgm to? 400? 375? is it even close? under 100 your dealing with +/- 20 points... maybe I am too picky, but when I wear the cgm I expect a "lil bit" of trust and accuracy.
[/quote]
Joe, I totally see what you mean, but that amount of inaccuracy isn't typical for my one touch meter. Usually, if I test twice in a row to calibrate after changing a sensor, I'll get readings like 187 and 182. While +/- 20 is allowed by the FDA, it's not typical. Granted, I don't have a lot of experience with high-high's because I'm rarely over 240, so maybe someone with a higher a1c has had a different experience.
The dexcom people, if you call them, don't recommend waiting until you come down. They do recommend using the same meter for consistency. But, the dexcom is more accurate during lows than highs, so they'll actually suggest an extra calibration when you're high if the readings are way off. I'm not sure which cgm you're on, but dexcom just wants you to be under 400 to calibrate. Even if I calibrate when I'm over 120, it's never affected the accuracy later...
I guess I'm just saying, why add a layer of complexity to the CGM when it's not necessary due to some vaguely potential problem. Worst comes to worst, I could just recalibrate later. In your example case, you just enter what your meter says, not make up a number in the middle of a supposed range. It actually works more smoothly than you'd think!
i don't want to argue, sarah, I am just disspaointed with ALL of our meter's accuracy, and I am also dissapointed with every manufacturer's cgm accuracy no matter what it says on the box, or what the rep says. so I often rant about +/- 20%. Meter accuracy is not vague at all, it's reality. even if your meter has a close grouping, it doens't make it more accurate, 4 readings in a row of 157 still means you are 188 to 125, in reality... which bothers me quite a bit, and so I rant.
I deal with instruments that are 0.04% accurate, every day. these instruments need claibration once every two years. These instruments have hysterisis and repetability that are so close and so good that it would make your hair stand up. so I get to see what real instrumentation can do, and then I look at my blood sugar meter and sigh. I look at my cgm, and I sometimes sigh twice. it's me.
Joe, I agree with you to an extent - but I also think it's important to keep in mind the other inaccuracies we deal with. Carb counting, for instance, is wildly inaccurate! Injections can vary by more than 20%. Figuring out basal rates can't get you even close to your bodies needs all the time.
It seems like getting a accurate home meter or an accurate cgm that required less calibrations might be a good first step, but diabetes management is always going to be totally inaccurate.
if you could get a 1% real time (not trademark "real time" but actual real-time) continuous glucose (not interstitial but blood glucose) monitor that doesen't ever need claibration, you would have the right tool to deal with all of the other combined inaccuracies. between 1 and 2 hours post prand. you could see exactly how a bad guess at carbs or how off an injection absorption was affecting you. you could also use it, effectively, for exercise.
If I had one I would immediately throw my one touch utlra out of a car window, and hang bananas from my pork protein interstitial half hour ago cgm.
in engineering there is 1 universal truth: if you can't measure it, you can't control it. no more ranting, or wishful thinking... I am depressing myself. I must repeat "at least it's better than clinitest... at least it's better than clinitest...at least it's better than clinitest... "
there. I am feeling better now